Valve system for compression ignition device



Aug. 24, 1965 D. F. BUTLER ETAL 3,202,055

VALVE SYSTEM FOR COMPRESSION IGNITION DEVICE Filed Nov. 1, 1963 M mm W5 N 0 M mm Y B Z 5 A TTORNEKV United States Patent 3,202,055 VALVE SYSTEM FOR COMPRESSION IGNITION DEVICE David F. Butler and Glenn R. Dixon, Hamden, Conn, assignors to Olin Mathieson Chemical Corporation, a corporation of Virginia Filed Nov. 1, 1963, Ser. No. 320,904

' Claims. (CL 89-7) This invention relates to valve systems suitable for use in firearms and tools powered by adiabatic compression of a liquid propellant.

It is known that certain liquid propellants can be compressed into a very small volume and caused to ignite. The compression ignition of the propellant produces high pressure gases which, if properly controlled, can be directed against a projectile or a Working piston to act as the propelling force for the projectile or bullet.

One of the basic essentials of a successful liquid propellant system is a valve system which will confine the propellant so that a high enough pressure can be obtained to propagate ignition. The valve must remain closed long enough after ignition to allow for the required pressure buildup and then open for a long enough interval to allow the gas pressure to be transferred from the combustion chamber to a projectile or Working piston.

It is therefore a feature of this invention to provide a novel valve system for a liquid propelled firearm or tool.

It is a further feature of this invention to provide a valve system for a liquid propelled firearm or tool which is simple in design, durable, and economical to manufacture.

. It is a further feature of this invention to provide a valve system for a liquid propelled firearm or tool which is capable of delivering gases at a predetermined pressure to a work performing element consistently.

It is a further feature of this invention to provide valve system for a liquid propelled device which will provide an effective seal during the compression stroke' while the propellant is compressed to ignition; will continue to seal against gas leakage until a predetermined pressure is attained; and will then quickly open within a fraction of a second and remain open until all the pressure has been exerted against a projectile or working piston.

These and other features and advantages of this invencombustion chamber 2 and is moved by means (not shown). toward one end by combustion chamber 2. Piston 3 compresses a liquid propellant which has been injected into combustion chamber 2 bypump means (not shown). The liquid propellant is compressed into a very small volume at a pressure sufiicient to cause compression ignition, and combustion of the propellant. A valve chamber 4 communicates with combustion chamber 3 through a reduced opening 5. A valve 6 is mounted for sliding movement in valve chamber 4. The forward end of valve chamber 4 is beveled to provide a valve seat 7 for the conical nose 8A of valve 6. The valve 6 comprises a forward end 8 which includes conical nose 8A, an intermediate guide portion 9 of enlarged diameter, and a rearwardly extending stem portion 10 of reduced diameter. Sealing means such as O-rings 8B prevent gases 3,Z2,055 Ce Patented Aug. 24, 1965 from bypassing the forward end of valve 6. A shoulder 11 is formed between intermediate guide portion 9 and stem 10. Valve 6 is urged onto valve seat 7 by spring 12 acting through a spring retainer 13 which pushes on the end of the valve stem 10. Snubber means 14 is mounted in the valve chamber 4 to buffer and limit the rearward movement of valve 6 and to retain the valve 6 in its rear ward position for a predetermined interval of time. The snubber means may comprise a steel disc 15 and a resilient plug 16. The resilient plug 16 is mounted in a tapered portion 17 of the valve chamber 4 and surrounds valve stem 19. A metallic liner 18 may be fitted on the inside of the resilient plug to improve its wearing characteristics. As the valve 6 moves rearwardly, the shoulder 11 of the valve engages steel disc 15 and causes the resilient plug to be compressed into the conical portion 17 of valve chamber 4. This causes the resilient plug 16 i to be compressed and tightly grip valve stem 10. A barrel chamber 19 has one end 20 communicating with valve chamber 4 so that hot gases are transferred directly from the combustion chamber to the barrel chamber as soon as valve 6 is opened. A working piston 21 is slidably mounted in barrel chamber 19 and is moved forward in the barrel chamber 19 by the gas pressure caused by the combustion of the liquid propellant to perform useful Work. Instead of piston 21, a projectile such as a bullet (not shown) may be positioned in the barrel chamber and accelerated by the hot gases of combustion.

The operation of the above described device will now be described.

A suitable liquid propellant is injected into the upper end of combustion chamber 2 by pump means (not shown). The compression piston 3 is moved toward the upper end of combustion chamber 2 to compress the liquid propellant into a very small volume on the order of .030 cubic inch. As soon as a pressure level on the order of 400 psi. is directed against the liquid propellant by means of piston 3, ignition occurs and the pressure in combustion chamber 2 rises rapidly to a range of about 50,000 psi. This pressure acts directly on the. tapered end 8 of valve 6 through reduced opening 5. The pressure causes valve 6 to move off valve seat 7 which im mediately exposes the entire area at the end of valve 6 to the pressure thus accelerating its rearward motion against spring 12.

The valve 6 is moved rearwardly with an acceleration on the order of 2.5 million f-t./sec. Within a quarter of an inch of travel, the valve builds up an energy level of about 200 ft./ lbs. which must be controlled by suitable snubber means if the valve is to function repeatedly over a large number of cycles. To control the valve, a snubber means 14 is provided which may comprise a metal disc 15 of steel or other suitable material and a resilient plug 16 which surrounds the stem 10 of piston 6. As valve 6 moves rearwardly against spring 12, shoulder 11 engages metal disc 15 and moves disc 15 rearwardly against resilient plug 16. The resilient plug 15 is compressed into the tapered portion 17 of the valve chamber and moves radially inwardly about valve stem 10 to grip and retain the valve long enough for the hot gases of combustion to pass into barrel chamber 1? and act on the working 'piston 21 positioned therein. The self-snubbing feature of snubber means 14 is an important function of my device. Should the valve 6 merely strike a solid surface, it would tend to rebound from the solid surface and close almost immediately, closing oif the flow of high pressure gas to the working piston. The trapped gas Would then expand its energy against compression piston 3 causing destructive forces in the system. With the snubber means, the valve 6 is gripped and retained long enough (.005 to .010 second) before the valve can return to a fully closed position to insure that the high pressure gas gives up its energy to the working piston 21.

FIGURE 2 shows another embodiment of the invention.

Referring now to FIGURE 2, a housing generally indicated 30 is provided. A combustion chamber 31 is provided in housing 30. A compression piston 32 is slidably mounted in combustion chamber 31 and is moved by means (not shown) to compress to ignite a liquid propellant which has been injected into the upper portion of combustion chamber 31 by pump means (not shown). The upper end of combustion chamber 31 communicates with a valve chamber 33. Valve chamber 33 includes a forward portion 34 of reduced diameter, an intermediate portion 35 and a rearward tapered portion 36. Mounted in the valve chamber 33 is a valve 37. The valve 37 includes a nose portion 38, an enlarged guide portion 39, and a stem portion '40. The nose portion 38 of the valve is tapered at 41 and is normally engaged against valve seat 42 formed in the forward end of valve chamber 33 to provide an effective gas seal. A shoulder 43 is formed on the nose portion 33 between the taper 41 and the enlarged guide portion 39. Gas pressure created by the combustion of the liquid propellant acts against shoulder 43 and moves the valve 37 rearwardly against a spring 45 and a spring retainer 46 which normally urge valve 37 against valve seat 42. As soon as valve 37 begins its rearward movement and moves away from valve seat 42, the entire area at the forward end of the valve is exposed to the gas pressure. This causes valve 37 to be accelerated rearwardly so that guide portion 39 engages snubber means 47. Snubber means 47 includes a disc 48 and a split resilient sleeve 49 which surrounds the valve stem 40. A major portion of split resilient sleeve 47 is positioned in the tapered portion 36 of valve chamber 33. A split metallic liner may be provided between stem 40 and sleeve 47 to reduce the effects of Wear on the resilient sleeve. Buffer means 45 functions to buifer and snub valve 36 in the same way as described with reference to the embodiment of FIGURE 1.

A plurality of sealing rings 38A are provided to prevent gases from leaking past the nose portion 38 of the valve.

A barrel chamber 51 has one end communicating with valve chamber 33 through reduced opening 52. A working piston 53 or a projectile such as a bullet (not shown) may be chambered in the barrel and accelerated by the hot gases of combustion when valve 37 is opened.

The principal advantage of the FIGURE 2 embodiment resides in the in-line arrangement or" the valve and the barrel chamber. Such an arrangement is more suitable for use in a weapon or tool having the conventional appearance of a firearm. In the FIGURE 2 embodiment, the hot gases under pressure act on shoulder 43 to initiate movement of the valve. In the FIGURE 1 embodiment, the gases act directly on the end of the valve. It is therefore apparent that in the FIGURE 2 embodiment, the problem of initially sealing the valve is somewhat more difiicult since there is a problem of sealing the valve at the valve seat 42 and around shoulder 43. In the FIG- URE 1 embodiment, gas pressure acts initially only against the valve seat 7 and this is the only area Where a perfect seal is required.

Other than the differences noted above, the operation of the FIGURE 2 device is identical to the operation of the FIGURE 1 device which has been described in detail above.

While this invention has been described in detail with reference to certain preferred embodiments, variations in design and mechanical modifications are contemplated which are within the spirit and scope of the appended claims.

What is claimed is:

1. In a device actuated by the adiabatic compression and ignition of a liquid propellant include a combustion chamber, a barrel chamber, a valve chamber communicating said combustion chamber with said barrel chamber, a compression piston slidably mounted in said combustion chamber, a valve seat formed between said valve chamber and said barrel chamber, a valve slidably mounted in said valvechamber, said valve having a conical nose portion normally positioned against said valve seat seal ing said barrel chamber from communication with said combustion chamber, spring means normally urging said nose portion of said valve into sealing engagement with said valve seat, a rearwardly extending stem formed integral with said Valve, and snubber means mounted in said valve chamber surrounding said stern operative to buffer rearward movement of said valve and to retain said valve in an open position for a predetermined interval of time.

2. The device of claim 1 further including an inwardly tapered portion in said valve chamber, said stem extending into said tapered portion of said valve chamber, an enlarged guide portion formed on said valve between said nose portion and said stem, said snubber means comprising a resilient plug positioned between said stem and the tapered portion of said valve chamber, said resilient plug being operative to bufier the rearward movement of said valve when the enlarged guide portion engages the plug and compresses the plug into the tapered portion of the valve chamber and operative to retain the valve in a rearward position for a predetermined interval of time by compressing inwardly about said stem as the plug is driven rearwardly into said tapered portion of said valve chamber.

3. The device of claim 2 further including a split sleeve positioned between said stem and said plug, and a disc positioned between said enlarged guide portion of said valve and said plug.

4. The device of claim 1 in which said barrel chamber and said piston chamber are axially aligned relative to one another and said combustion chamber is positioned at an angle relative to said barrel and valve chambers.

5. The device of claim 1 in which said valve chamber, said combustion chamber, and said barrel chamber are all arranged at an angle relative to each other which is less than a straight angle.

References Cited by the Examiner UNITED STATES PATENTS 2,129,875 9/38 Rost 897 2,302,242 11/42 Miller 25164 2,574,147 11/51 Hobbs 89-7 2,947,221 8/60 Grifiin et a1. 89-7 3,046,737 7/62 Ottestad 89-7X 3,072,143 1/63 Fleischhacker 25164 X 3,074,428 1/ 63 Mancewicz 251-64X FOREIGN PATENTS 571,163 8/45 Great Britain 12411 BENJAMIN A. BORCHELT, Primary Examiner.

SAMUEL W. ENGLE, Examiner. 

1. IN A DEVICE ACTUATED BY THE ADIABATIC COMPRESSION AND IGNITION OF A LIQUID PROPELLANT INCLUDE A COMBUSTION CHAMBER, A BARREL CHAMBER, A VALVE CHAMBER COMMUNICATING SAID COMBUSTION CHAMBER WITH SAID BARREL CHAMBER, A COMPRESSION PISTON SLIDABLY MOUNTED IN SAID COMBUSTION CHAMBER, A VALVE SEAT FORMED BETWEEN SAID VALVE CHAMBER AND SAID BARREL CHAMBER, A VALVE SLIDABLY MOUNTED IN SAID VALVE CHAMBER, SAID VALVE HAVING A CONICAL NOSE PORTION NORMALLY POSITIONED AGAINST SAID VALVE SEAT SEALING SAID BARREL CHAMBER FROM COMMUNICATION WITH SAID COMBUSTION CHAMBER, SPRING MEANS NORMALLY URGING SAID NOSE PORTION OF SAID VALVE INTO SEALING ENGAGEMENT WITH SAID VALVE SEAT, A REARWARDLY EXTENDING STEM FORMED INTEGRAL WITH SAID VALVE, SAID SNUBBER MEANS MOUNTED IN SAID VALVE CHAMBER SURROUNDING SAID STEM OPERATIVE TO BUFFER REARWARD MOVEMENT OF SAID VALVE AND TO RETAIN SAID VALVE IN AN OPEN POSITION FOR A PREDETERMINED INTERVAL OF TIME. 